| In this paper, the fumigation effect of five essential oils, Allium sativum L (AS),Syzygium aromaticum (L.)(SA) Merr.&Perr.(SA), Litsea cubeba (Lour.) Pers.(LC),Coriandrum sativum L.(CS) and Eucalyptus globulus Labill.(EG) against eggs and adults ofCallosobruchus chinensis Linnaeus were evaluated to screen out single essential oils withhigher fumigation activity. Then single essential oils were mixed to screen out complexedwith higher fumigation activity. At last, essential oils were absored in porous starch andformulated into slow-release formulations and its ovicidal activity and desorption propertiesdetermine were evaluated. The fumigant residue of essential oils in the mung bean was alsostudied with headspace solid-phase micro extraction and gas chromatography(HS-SPME-GC). The main results are as followings:(1) All plant essential oils have fumigation action against C. chinensis. When thefumigation period was72h, the LC50values of garlic oil, clove oil, litsea cubeba oil, corianderessential oil and eucalyptus oil were0.34μL/L,1.12μL/L,3.78μL/L,5.29μL/L and86.32μL/L, respectively. In addition, the garlic oil and eucalyptus oil showed high fumigationactivity against adults, with the LC50values of7.73μL/L,26.88μL/L respectively. It couldbe concluded that the eggs of C. chinensis showed higher sensitivity to essential oils thanadults.(2) Because garlic oil and clove oil that showed higher fumigation activity against C.chinensis eggs, they were used as the main component in complexes. Other essential oilswere mixed with them with the equivalent volume. The results showed that the ovicidal effectwas the best when garlic oil was mixed with clove oil or clove oil mixed with Litsea cubebaoil. When these two composite essential oils were mixed tested in different ratio, it was foundthat they can achieve the best fumigation effect against eggs when the ratio were7:1. Whenthe concentration of these two composite essential oils were0.8μL/L and1.4μL/L, thecorrect mortality of eggs reached75.78%and71.75%respectively after72h fumigation.Besides, when the garlic oil mixed with clove oil (7:1) and eucalyptus oil mixed with cloveoil (5:1) showed better fumigation activity against adults at the concentration of12μL/L and35μL/L, and the correct mortality of adults were66.90%and76.06%respectively.(3) Porous starch was chosed as the carrier and essential oils were made into slow-release formulations. The results showed that the slow-release formulation had goodfumigation effect against eggs of C. chinensis. When the slow-release formulation containgcomposites of garlic oil/clove oil or clove oil/Litsea cubeba oil at the concentrations of32μL/L and64μL/L respectively, the correct mortality of eggs was100%. The slow-releaseformulation can slow the release of plant essential oils to a certain extent. When theslow-release formulation contained garlic oil/clove oil composite at the concentration of32μL/L and64μL/L, the formulations showed strong fumigation activity against eggs during3d and9d respectively. When the concentration of clove oil mixed with Litsea cubeba oil were64μL/L and128μL/L, the useful life of slow-release formulation all were3d, and thecorrect mortality of the slow-release formulation against eggs of C. chinensis was over80%after72h during the useful life.(4) The residue of the plant essential oils in the mung bean was determined byHS-SPME-GC. The results showed that the residue of garlic oil and clove oil in the mungbean was low relatively, and the residue concentration was less than0.05μL/L when thefumigation apparatus was ventilated for13d. |
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